From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
To: pgsql-performance@postgresql.org
Subject: Re: Background writer configuration
Date: Wed, 15 Mar 2006 11:54:33 -0800
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> I then did some calculations, based on the sustained write speed of our
> drive array (as measured by copying big files to it), and we tried
> this:
>
> bgwriter_lru_percent = 20.0
> bgwriter_lru_maxpages = 200
> bgwriter_all_percent = 10.0
> bgwriter_all_maxpages = 600
>
> This almost totally eliminated the clusters of timeouts, and caused the
> transaction application rate to increase by a factor of eight over the
> already-improved speed.  (That is, we were running 30 to 35 times as
> many transactions per minute into the database, compared to the default
> background writer configuration.)  I'm going to let these settings
> settle in for a week or two before we try adjusting them further (to see
> if we can eliminate those last few timeouts of this type).


Can you tell us what type of array you have?

Joshua D. Drake

>
> I guess my point is that people shouldn't be shy about boosting these
> numbers by a couple orders of magnitude from the default values.  It may
> also be worth considering whether the defaults should be something more
> aggressive.
>
> -Kevin
>
>
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